1) American milkwort 2) Plant of the milkwort family 3) Root 
• (n.) Seneca root.
Sen'e·ga noun (Medicine) Seneca root. 
Type: Term Pronunciation: sen′e-gă Definitions: 1. The dried root of Polygala senega (family Polygalaceae), an herb of eastern and central North America; an expectorant. Synonyms: Seneca snakeroot
Senega (Polygala senega) is a North American plant, introduced into Britain during the 18th century, growing to some twenty centimetres tall and bearing terminal spikes of small, dull-white coloured flowers. The woody root of the plant was used by American Indians as an antidote to the bite of the rattlesnake, and is used in medicine to treat bronc...
[n] - dried root of two plants of the genus Polygala containing an irritating saponin 2. [n] - perennial bushy herb of Central and southern United States having white flowers with green centers and often purple crest
noun perennial bushy herb of central and southern United States having white flowers with green centers and often purple crest; similar to Seneca snakeroot